Sink



FIG. 1 is a perspective view of a sink embodying my design.

FIG. 2 is a top plan view of the design shown in FIG. 1.

FIG. 3 is a front view of the design shown in FIG. 1; and,

FIG. 4 is a right side view of the design shown in FIG. 1.

The broken line showing of the environment is for illustrative purposes only and forms no part of the claimed design. The broken lines which define the boundaries of the claimed design form no part thereof. The bottom and rear view are not part of the claimed design. 

I claim the ornamental design for a sink, as shown and described. 